1. Field of the Invention
The present invention relates to a method of inspecting an optical waveguide substrate comprising an optical waveguide disposed on a substrate, and a method of inspecting an optical component mounted on an optical waveguide substrate.
2. Description of the Related Art
Optical communications technologies using light as an information transmitting medium have been in widespread usage. According to the optical communications technologies, an optical waveguide substrate comprising an optical waveguide disposed on a substrate is used for transmitting an optical signal which represents light modulated by an information signal, and the optical signal is transmitted along the optical waveguide substrate. The optical waveguide substrate comprises a core layer having a high refractive index and a cladding layer having a low refractive index, the core layer being surrounded by the cladding layer. An optical signal which has entered one end of the optical waveguide at a critical angle or a smaller angle is confined within the core layer and travels through the core layer while being repeatedly and totally reflected by the boundary between the core layer and the cladding layer, and finally leaves the optical waveguide from its other end.
Optical waveguide substrates used in the optical communications technologies are required to transmit an optical signal along the optical waveguide on the substrate with a high efficiency. In order for a completed optical waveguide substrate to meet such a requirement, the completed optical waveguide substrate is inspected for an amount of light that is conducted through the optical waveguide. Japanese laid-open patent publication No. 11-304643, for example, discloses a method of inspecting an amount of light that is conducted through an optical waveguide. The disclosed method is carried out using inspecting apparatus 100 shown in FIG. 1 of the accompanying drawings. As shown in FIG. 1, inspecting apparatus 100 comprises light source 104 disposed on the side of an end face of optical waveguide array 101 to be inspected and including semiconductor laser 102 and condensing lens 103, feed mechanism 105 comprising a drive motor, a feed screw, and a feed slide, for translating light source 104 along optical waveguide array 101, light detector 106 disposed on the side of the other end face of optical waveguide array 101, and personal computer 107 connected to light detector 106.
For inspecting an amount of light that is conducted through optical waveguide array 101 using inspecting apparatus 100, light source 104 is mechanically translated by feed mechanism 105 and, while light source 104 is being thus translated, it is energized to apply laser beam 108 to the end of optical waveguide array 101 to successively scan unit cells thereof. Light beams emitted from the other end of optical waveguide array 101 are detected by light detector 106, which generates a detected signal that is processed by personal computer 107 to inspect an amount of light that is conducted through optical waveguide array 101.
According to the above conventional inspecting method, since light source 104 is moved by feed mechanism 105 to apply the laser beam successively to the unit cells of optical waveguide array 101, the inspecting rate is low. Furthermore, because the light beams emitted from the respective unit cells of optical waveguide array 101 are detected altogether by light detector 106, it is difficult to inspect cross-talk.
Specifically, as shown in FIG. 1, inasmuch as while light source 104 is being mechanically translated by feed mechanism 105, light source 104 is energized to apply laser beam 108 to successively scan unit cells of optical waveguide array 101, it is time-consuming to scan optical waveguide array 101 and detect light beams emitted from optical waveguide array 101, resulting in a low inspecting rate.
According to the above conventional inspecting method, inasmuch as the light beams emitted from the respective unit cells of optical waveguide array 101 are detected altogether by light detector 106, as shown in FIG. 1, it is unable to distinguish the light beams emitted from the individual unit cells from each other, resulting in difficulty to inspect cross-talk.